阅读说明：本技术 一种氮化硼/碳纳米管/聚酰亚胺复合材料的制备方法 (Preparation method of boron nitride/carbon nano tube/polyimide composite material ) 是由 周雨薇 于 2021-09-02 设计创作，主要内容包括：本发明涉及一种氮化硼/碳纳米管/聚酰亚胺复合材料的制备方法。该复合材料的制备方法为先将微米氮化硼通过水热法制备成氮化硼纳米片,然后通过硅烷偶联剂KH550对其进行改性；同时将碳纳米管经过酸化处理,得到羧基碳纳米管,然后将改性氮化硼与羧基碳纳米管在溶剂中复合后,向体系中加入二元胺的四羧酸二酸酐单体,制备聚酰胺酸,最后将添加有氮化硼/碳纳米管复合填料的聚酰胺酸溶液烘干溶剂后高温脱水亚胺化得到氮化硼/碳纳米管/聚酰亚胺复合材料。本发明通过同时调控氮化硼与碳纳米管的比例调控填料粒子的微观结构,从而调控复合材料的导热性能,本发明所制备得到的复合材料热导率大于0.6W/mK,电阻率大于1×10～(11)Ωm。(The invention relates to a preparation method of a boron nitride/carbon nano tube/polyimide composite material. The preparation method of the composite material comprises the steps of firstly preparing micron boron nitride into boron nitride nanosheets by a hydrothermal method, and then modifying the boron nitride nanosheets by a silane coupling agent KH 550; simultaneously, acidifying the carbon nano tube to obtain a carboxyl carbon nano tube, compounding the modified boron nitride and the carboxyl carbon nano tube in a solvent, adding a tetracarboxylic dianhydride monomer of diamine into the system to prepare polyamic acid, and finally drying the polyamic acid solution added with the boron nitride/carbon nano tube composite fillerDehydrating and imidizing the solvent at high temperature to obtain the boron nitride/carbon nano tube/polyimide composite material. The microstructure of the filler particles is regulated and controlled by simultaneously regulating and controlling the proportion of the boron nitride and the carbon nano tubes, so that the heat conduction performance of the composite material is regulated and controlled, the thermal conductivity of the composite material prepared by the method is more than 0.6W/mK, and the resistivity is more than 1 x 10 11 Ωm。)

1. A preparation method of a boron nitride/carbon nano tube/polyimide composite material is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) dispersing commercially available micron boron nitride in 2-10 mol/L sodium hydroxide solution to prepare 2-10 g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W for 2-10 h, transferring the dispersion to a hydrothermal kettle, reacting at 130-180 ℃ for 4-12 h, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral with deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 2-10 h to obtain boron nitride nanosheets;

(2) adding a silane coupling agent KH550 into a 95% ethanol aqueous solution to prepare a 0.1-1 wt% solution, then adding the boron nitride nanosheet obtained in the step (1), stirring and reacting for 4-12 h at 40-70 ℃, and spin-drying the solvent to obtain silane coupling agent modified boron nitride, wherein the mass ratio of the silane coupling agent to the boron nitride is 1: 10-30;

(3) adding a commercially available carbon nanotube into a mixed solution of concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1, stirring and reacting for 4-12 h at 40-70 ℃, filtering, washing to be neutral by deionized water, and drying in vacuum to obtain a carboxyl carbon nanotube, wherein the ratio of the carbon nanotube to the mixed acid is 1 g: 10-80 mL;

(4) mixing a carboxyl carbon nano tube and modified boron nitride according to a mass ratio of 1: 3-10, adding the mixture into N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2-10 hours in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W at room temperature to obtain the boron nitride/carbon nanotube filler, wherein the concentration of the carboxyl carbon nanotube is 0.1-0.5 wt%;

(5) under the protection of nitrogen atmosphere, adding diamine monomer into the system in the step (4), then adding tetracarboxylic dianhydride into the system in 0.5-1 h, stirring and reacting for 8-16 h at room temperature to obtain a mixed solution of boron nitride/carbon nano tube/polyamic acid, wherein diamine is more than one of p-phenylenediamine, 4,4 '-diaminodiphenyl ether, 4, 4' -diaminobenzene sulfone and 4,4 '-diaminodiphenylmethane, tetracarboxylic dianhydride is more than one of pyromellitic dianhydride, 4, 4' -biphenyltetracarboxylic anhydride and 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, and the molar ratio of diamine to tetracarboxylic dianhydride is 1: 1, the concentration of diamine is 0.1-0.5 mol/L;

(6) and (3) casting the mixed solution obtained in the step (5) on a glass plate, drying in an oven at 120-180 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280-330 ℃ for 1-3 h, naturally cooling to room temperature, and stripping the sample from the glass plate to obtain the composite film.

Technical Field

The invention relates to a preparation method of a boron nitride/carbon nano tube/polyimide composite material, belonging to the field of heat-conducting composite materials. The heat-conducting insulating compound prepared by the invention can be used as a heat-conducting material to be applied to the fields of electronic devices, electronic packaging, integrated circuits and the like.

Background

Polyimide (PI) refers to a high-performance engineering plastic containing imide ring (-CO-N-CO-) in the main chain. Polyimide can be widely applied to the fields of aerospace, microelectronics, lithium ion battery separation membranes and the like, mainly because the high temperature resistance of polyimide can reach more than 400 ℃, and the polyimide has extremely long service life within the temperature range of-200 ℃ to 300 ℃, and due to the advantages, the polyimide is called as one of polymer materials with optimal comprehensive performance in engineering plastics.

Boron nitride is a typical two-dimensional ceramic material because of its similar interlayer structure to graphene, also known as "white graphite". Boron nitride has excellent insulating properties, high thermal conductivity, excellent mechanical properties, and corrosion resistance. However, since the interlayer structure is stable, it is chemically inactive, and is often modified for reaction and utilization. The carbon nano tube is used as a one-dimensional nano material, has light weight, large length-diameter ratio and perfect connection of a hexagonal structure, and has excellent mechanical, electrical and chemical properties. The boron nitride and the carbon nano tube are both excellent heat conducting materials, and the two materials are combined to build a network structure of a one-dimensional two-dimensional material.

The invention selects boron nitride and carbon nano tube as the filled heat conducting particles to increase the heat conducting property of the composite material. Compared with the prior art, the boron nitride particles grafted with amino groups have positive electric property, the carboxyl groups on the carbon nano tubes have negative electric property, and the two fillers have electrostatic interaction due to the opposite electric property, so that the two fillers are connected more tightly.

Disclosure of Invention

The invention aims to solve the problems that the existing polyimide has poor heat-conducting property and the electric conductivity of the polyimide is increased after the conductive filler or graphene and other fillers are added, and provides a preparation method of a boron nitride/carbon nano tube/polyimide composite material. The preparation method specifically comprises the steps of preparing micron boron nitride into boron nitride nanosheets, modifying the boron nitride nanosheets by using a silane coupling agent KH550, acidifying the carbon nanotubes to obtain carboxyl carbon nanotubes, compounding the modified boron nitride and the carboxyl carbon nanotubes, adding a tetracarboxylic acid dianhydride monomer of diamine into a system, preparing polyamic acid in situ, drying a polyamic acid solution added with the boron nitride/carbon nanotube composite filler by using a solvent, and performing high-temperature dehydration and imidization to obtain the boron nitride/carbon nanotube/polyimide composite material.

The preparation method of the boron nitride/carbon nano tube/polyimide composite material is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) dispersing commercially available micron boron nitride in 2-10 mol/L sodium hydroxide solution to prepare 2-10 g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W for 2-10 h, transferring the dispersion to a hydrothermal kettle, reacting at 130-180 ℃ for 4-12 h, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral with deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 2-10 h to obtain boron nitride nanosheets;

(2) adding a silane coupling agent KH550 into a 95% ethanol aqueous solution to prepare a 0.1-1 wt% solution, then adding the boron nitride nanosheet obtained in the step (1), stirring and reacting for 4-12 h at 40-70 ℃, and spin-drying the solvent to obtain silane coupling agent modified boron nitride, wherein the mass ratio of the silane coupling agent to the boron nitride is 1: 10-30;

(3) adding a commercially available carbon nanotube into a mixed solution of concentrated hydrochloric acid and concentrated nitric acid in a volume ratio of 3:1, stirring and reacting for 4-12 h at 40-70 ℃, filtering, washing to be neutral by deionized water, and drying in vacuum to obtain a carboxyl carbon nanotube, wherein the ratio of the carbon nanotube to the mixed acid is 1 g: 10-80 mL;

(4) mixing a carboxyl carbon nano tube and modified boron nitride according to a mass ratio of 1: 3-10, adding the mixture into N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2-10 hours in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W at room temperature to obtain the boron nitride/carbon nanotube filler, wherein the concentration of the carboxyl carbon nanotube is 0.1-0.5 wt%;

(5) under the protection of nitrogen atmosphere, adding diamine monomer into the system in the step (4), then adding tetracarboxylic dianhydride into the system in 0.5-1 h, stirring and reacting for 8-16 h at room temperature to obtain a mixed solution of boron nitride/carbon nano tube/polyamic acid, wherein diamine is more than one of p-phenylenediamine, 4,4 '-diaminodiphenyl ether, 4, 4' -diaminobenzene sulfone and 4,4 '-diaminodiphenylmethane, tetracarboxylic dianhydride is more than one of pyromellitic dianhydride, 4, 4' -biphenyltetracarboxylic anhydride and 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, and the molar ratio of diamine to tetracarboxylic dianhydride is 1: 1, the concentration of diamine is 0.1-0.5 mol/L;

(6) and (3) casting the mixed solution obtained in the step (5) on a glass plate, drying in an oven at 120-180 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280-330 ℃ for 1-3 h, naturally cooling to room temperature, and stripping the sample from the glass plate to obtain the composite film.

The invention has the beneficial effects that: the boron nitride/carbon nano tube composite filler is formed by simultaneously adding the modified boron nitride and the carboxyl carbon nano tube. The carbon nano tube is a one-dimensional linear material, has higher length-diameter ratio and light weight, and can form a plurality of filler particles with smaller adding amount. The boron nitride is microscopically oriented along the carbon nanotubes, and the dispersed boron nitride is connected to form a complete heat conducting network. Thus boron nitride is both a thermally conductive filler and a connecting bridge. The modified boron nitride enables the boron nitride to be easily combined with the carbon nano tube, and simultaneously the proportion of the boron nitride to the carbon nano tube is regulated and controlled to regulate and control the microstructure of the filler particles, so that the heat conduction performance of the composite material is regulated and controlled, the thermal conductivity of the composite material prepared by the invention is more than 0.6W/mK, and the resistivity is more than 1 multiplied by 10¹¹Ωm。

Drawings

FIG. 1 is a schematic diagram of preparation of boron nitride/carbon nanotube composite filler

Detailed Description

The following examples of the preparation process of the present invention are presented, but the following examples are illustrative of the present invention and do not constitute any limitation to the claims of the present invention.

Example 1

(1) Dispersing commercially available micron boron nitride in 5mol/L sodium hydroxide solution to prepare 4g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W for 2h, transferring the dispersion to a hydrothermal kettle, reacting for 6h at 150 ℃, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral by deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 8h to obtain boron nitride nanosheets;

(2) adding a silane coupling agent KH550 into a 95% ethanol aqueous solution to prepare a 0.5 wt% solution, then adding the boron nitride nanosheet obtained in the step (1), stirring at 60 ℃ for reacting for 8 hours, and spin-drying the solvent to obtain silane coupling agent modified boron nitride, wherein the mass ratio of the silane coupling agent to the boron nitride is 1: 10;

(3) adding 1g of commercially available carbon nanotube into a mixed solution of 30mL of concentrated hydrochloric acid and 10mL of concentrated nitric acid, stirring and reacting for 4h at 70 ℃, filtering, washing with deionized water to be neutral, and drying in vacuum to obtain a carboxyl carbon nanotube;

(4) adding 0.1g of carboxyl carbon nano tube and 0.5g of modified boron nitride into 100g of N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2h in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W at room temperature to obtain boron nitride/carbon nano tube filler;

(5) under the protection of nitrogen atmosphere, adding 2.1g of 4, 4' -diaminodiphenyl ether into the system in the step (4), then adding 2.3g of pyromellitic anhydride within 0.5h, and stirring and reacting for 12h at room temperature to obtain a mixed solution of boron nitride/carbon nano tube/polyamic acid;

(6) casting the mixed solution obtained in the step (5) on a glass plate, drying in an oven at 150 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 300 ℃ for 2h, naturally cooling to room temperature, stripping a sample from the glass plate to obtain the composite material, wherein the thermal conductivity of the composite material reaches 0.6W/mK, and the resistance is 2.0 multiplied by 10¹¹Ωm。

Example 2

(1) In accordance with example 1, step (1);

(2) adding a silane coupling agent KH550 into a 95% ethanol aqueous solution to prepare a 0.5 wt% solution, then adding the boron nitride nanosheet obtained in the step (1), stirring at 60 ℃ for reacting for 8 hours, and spin-drying the solvent to obtain silane coupling agent modified boron nitride, wherein the mass ratio of the silane coupling agent to the boron nitride is 1: 20;

(3) in accordance with example 1, step (3);

(4) in accordance with step (4) of example 1;

(5) in accordance with example 1, step (5);

(6) consistent with the step (6) of the example 1, the thermal conductivity of the composite material reaches 0.7W/mK, and the electric resistance is 1.5 multiplied by 10¹¹Ωm。

Example 3

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) adding 0.1g of carboxyl carbon nano tube and 1g of modified boron nitride into 100g of N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2h in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W at room temperature to obtain boron nitride/carbon nano tube filler;

(5) in accordance with example 1, step (5);

(6) consistent with the step (6) of the example 1, the thermal conductivity of the composite material reaches 0.7W/mK, and the electric resistance is 1.8 multiplied by 10¹¹Ωm。

Example 4

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) in accordance with step (4) of example 1;

(5) under the protection of nitrogen atmosphere, adding 2.6g of 4, 4' -diamino phenylsulfone into the system in the step (4), then adding 2.3g of pyromellitic dianhydride within 0.5h, and stirring and reacting for 12h at room temperature to obtain a mixed solution of boron nitride/carbon nano tube/polyamic acid;

(6) consistent with the step (6) of the example 1, the thermal conductivity of the composite material reaches 0.6W/mK, and the electric resistance is 2.0 multiplied by 10¹¹Ωm。

Example 5

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) in accordance with step (4) of example 1;

(5) in accordance with example 1, step (5);

(6) casting the mixed solution obtained in the step (5) on a glass plate, drying in an oven at 160 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280 ℃ for 3h, naturally cooling to room temperature, stripping a sample from the glass plate to obtain the composite material, wherein the thermal conductivity of the composite material reaches 0.6W/mK, and the resistance is 2.0 multiplied by 10¹¹Ωm。